DEP 31.29.06.30-Gen.pdf

TECHNICAL SPECIFICATION CENTRIFUGAL SUBMERGED MOTOR PUMPS (IN REFRIGERATED PRODUCT OR PRESSURISED STORAGE SERVICE) DEP 31.29.06.30-Gen. December 1996 (DEP Circular 25/97 has been incorporated) DESIGN AND ENGINEERING PRACTICE USED BY COMPANIES OF THE ROYAL DUTCH/SHELL GROUP This document is confidential. Neither the whole nor any part of this document may be disclosed to any third party without the prior written consent of Shell International Oil Products B.V. and Shell International Exploration and Production B.V., The Hague, The Netherlands. The copyright of this document is vested in these companies. All rights reserved. Neither the whole nor any part of this document may be reproduced, stored in any retrieval system or transmitted in any form or by any means (electronic, mechanical, reprographic, recording or otherwise) without the prior written consent of the copyright owners. PREFACE DEP (Design and Engineering Practice) publications reflect the views, at the time of publication, of: Shell International Oil Products B.V. (SIOP) and Shell International Exploration and Production B.V. (SIEP) and Shell International Chemicals B.V. (SIC) The Hague, The Netherlands, and other Service Companies. They are based on the experience acquired during their involvement with the design, construction, operation and maintenance of processing units and facilities, and they are supplemented with the experience of Group Operating companies. Where appropriate they are based on, or reference is made to, national and international standards and codes of practice. The objective is to set the recommended standard for good design and engineering practice applied by Group companies operating an oil refinery, gas handling installation, chemical plant, oil and gas production facility, or any other such facility, and thereby to achieve maximum technical and economic benefit from standardization. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where DEPs may not cover every requirement or diversity of condition at each locality. The system of DEPs is expected to be sufficiently flexible to allow individual operating companies to adapt the information set forth in DEPs to their own environment and requirements. When Contractors or Manufacturers/Suppliers use DEPs they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the DEPs. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor. The right to use DEPs is granted by SIOP, SIEP or SIC, in most cases under Service Agreements primarily with companies of the Royal Dutch/Shell Group and other companies receiving technical advice and services from SIOP, SIEP or SIC. Consequently, three categories of users of DEPs can be distinguished: 1)Operating companies having a Service Agreement with SIOP, SIEP, SIC or other Service Company. The use of DEPs by these Operating companies is subject in all respects to the terms and conditions of the relevant Service Agreement. 2)Other parties who are authorized to use DEPs subject to appropriate contractual arrangements. 3)Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) or 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards. Subject to any particular terms and conditions as may be set forth in specific agreements with users, SIOP, SIEP and SIC disclaim any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any DEP, combination of DEPs or any part thereof. The benefit of this disclaimer shall inure in all respects to SIOP, SIEP, SIC and/or any company affiliated to these companies that may issue DEPs or require the use of DEPs. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, DEPs shall not, without the prior written consent of SIOP and SIEP, be disclosed by users to any company or person whomsoever and the DEPs shall be used exclusively for the purpose for which they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of SIOP and SIEP. The copyright of DEPs vests in SIOP and SIEP. Users shall arrange for DEPs to be held in safe custody and SIOP or SIEP may at any time require information satisfactory to them in order to ascertain how users implement this requirement. All administrative queries should be directed to the DEP Administrator in SIOP. NOTE: In addition to DEP publications there are Standard Specifications and Draft DEPs for Development (DDDs). DDDs generally introduce new procedures or techniques that will probably need updating as further experience develops during their use. The above requirements for distribution and use of DEPs are also applicable to Standard Specifications and DDDs. Standard Specifications and DDDs will gradually be replaced by DEPs. DEP 31.29.06.30-Gen. December 1996 Page 2 TABLE OF CONTENTS 1.INTRODUCTION.4 1.1SCOPE 4 1.2DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS4 1.3DEFINITIONS 4 1.4CROSS-REFERENCES6 2.DESIGN. 7 2.1GENERAL 7 2.2NOISE CONTROL.7 2.3ELECTRIC MOTORS7 2.4CRITICAL SPEEDS.8 2.5VIBRATION AND BALANCE.8 2.6PRESSURE CASING DESIGN.9 2.7NOZZLES AND MISCELLANEOUS CONNECTIONS9 2.8SUCTION AND DISCHARGE FLANGES OF POTS (FOR POT-MOUNTED PUMPS). 9 2.9BOLTING. 10 2.10IMPELLERS. 10 2.11WEAR RINGS.10 2.12RUNNING CLEARANCES.10 2.13BEARINGS 10 2.14MISCELLANEOUS11 3.MATERIALS 12 3.1GENERAL 12 3.2MATERIAL INSPECTION12 3.3SUCTION POTS12 4.SHOP INSPECTION AND TESTS13 4.1GENERAL 13 4.2DIMENSIONAL CHECK13 4.3INTERNAL CHECK.13 4.4ELECTRIC MOTOR TEST13 4.5HYDROSTATIC TEST.13 4.6PERFORMANCE TEST14 4.7NET POSITIVE SUCTION HEAD TEST.15 4.8PUMP DOWN TEST.16 4.9POST TEST DISASSEMBLY16 4.10FOOT VALVE TEST16 4.11LIFTING CABLE TENSILE TEST16 5.REFERENCES17 APPENDICES APPENDIX 1RECOMMENDED CLEARANCES FOR CENTRIFUGAL SUBMERGED MOTOR PUMPS IN REFRIGERATED OR PRESSURISED STORAGE SERVICE20 DEP 31.29.06.30-Gen. December 1996 Page 3 1.INTRODUCTION 1.1SCOPE This DEP specifies requirements and gives recommendations for centrifugal submerged motor pumps in refrigerated product or pressurised storage service, whether column- mounted or pot-mounted. This DEP shall be used in conjunction with data/requisition sheet DEP 31.29.02.93-Gen. for centrifugal pumps. This DEP is a revision of an earlier publication with the same number, dated September 1982. In the event of conflict between documents relating to the enquiry or order, the following hierarchy shall apply: upper level:the purchase order and variations thereto second level:data/requisition sheets and drawings third level:this DEP 1.2DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS Unless otherwise authorised by SIOP and SIEP, the distribution of this DEP is confined to companies forming part of or managed by the Royal Dutch/Shell Group. It may be distributed to Manufacturers nominated by them (i.e. the distribution code is “F“, as defined in DEP 00.00.05.05-Gen.). This DEP is intended for use in oil refineries, chemical plants, gas plants and, where applicable, in exploration and production facilities and supply/ marketing installations. If national and/or local regulations exist in which some of the requirements may be more stringent than in this DEP, the Contractor shall determine by careful scrutiny which of the requirements are the more stringent and which combination of requirements will be acceptable as regards safety, economic and legal aspects. In all cases the Contractor shall inform the Principal of any deviation from the requirements of this document which is considered to be necessary in order to comply with national and/or local regulations. The Principal may then negotiate with the Authorities concerned with the object of obtaining agreement to follow this document as closely as possible. 1.3DEFINITIONS 1.3.1General definitions The Contractor is the party which carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project or operation of a facility. The Principal may undertake all or part of the duties of the Contractor. The Manufacturer/Supplier is the party which manufactures or supplies equipment and services to perform the duties specified by the Contractor. The Principal is the party which initiates the project and ultimately pays for its design and construction. The Principal will generally specify the technical requirements. The Principal may also include an agent or consultant authorised to act for, and on behalf of, the Principal. The word shall indicates a requirement. The word should indicates a recommendation. DEP 31.29.06.30-Gen. December 1996 Page 4 1.3.2Specific definitions -Best efficiency point is the flow at which a pump achieves its highest efficiency. -Continuous service for this pump type is an uninterrupted operation period of at least 16 000 hours under the specified conditions for the guarantee point, unless otherwise specified. -Guarantee point is the normal operating point as specified on the data/requisition sheet and the point at which the Manufacturer certifies that performance of the pump is within the tolerances specified (ref. API 610, section 4.3.1.1.). At least the following data shall be shown on the data/requisition sheets for this point: flow, total differential head, rated suction pressure, density and viscosity of the pumped liquid, NPSHA and speed. -Intermittent service is operation, including intentional stops and starts, under the conditions specified for the guarantee point. -Maximum allowable casing working pressure is the greatest pressure at the specified pumping temperature for which the pump casing is designed. This pressure shall be equal to or greater than the maximum differential pressure across the pump. -Maximum discharge pressure is the maximum suction pressure plus the maximum differential head which the pump would be able to develop when operating at the specified conditions of speed, maximum density and lowest pumping temperature with the maximum impeller size installed. -Maximum rated discharge pressure is the maximum suction pressure plus the maximum differential head which the pump would be able to develop when operating at the specified conditions of speed, maximum density and lowest pumping temperature with the furnished impeller size installed. -Maximum suction pressure is the highest suction pressure to which the pump may be subjected during operation. -Minimum flow is the higher of the two minimum flows defined below. Minimum flow does not refer to the minimum required process flow. -Minimum continuous thermal flow is the lowest flow at which the pump can operate without its operation being impaired by the temperature rise of the pumped liquid. -Minimum continuous stable flow is the lowest flow at which the pump can operate without exceeding the vibration limits imposed by this DEP. -Net positive suction head (NPSH) is the total suction head determined at the suction flange (bell mouth) of the pump minus the vapour pressure of the liquid at the highest temperature specified. Both suction head and vapour pressure are expressed in metres liquid absolute. -Net positive suction head available (NPSHA) shall be determined by the Principal for the pumping system. NPSHA is the total suction head determined at a reference location (see below) minus the vapour pressure of the liquid at the highest temperature specified and at rated flow. Both suction head and vapour pressure are expressed in metres liquid absolute. For pot-mounted pumps, the NPSHA is referenced to the suction flange of the pot. For column-mounted pumps, the NPSHA is referenced to the suction flange (bell mouth) of the pump. -Net positive suction head required (NPSHR) is the minimum NPSH required at rated flow and at highest specified liquid temperature to prevent a head drop of more than 3 percent due to cavitation within the pump. This requirement is also applicable to multi- stage pumps when the NPSHR is established by a head drop measurement across the first impeller only; otherwise a head drop limitation of 1% over the total differential head shall be applied. The NPSHR is determined by the Manufacturer and shall be based on the pump handling the actual product specified on the data/requisition sheet. It shall be referenced to the suction flange (bell mouth) of the pump and expressed in metres of DEP 31.29.06.30-Gen. December 1996 Page 5 actual liquid (water). -Pressure casing comprises all stationary pressure-containing parts of the complete pump unit, including all nozzles or other parts attached thereto subject to a differential pressure greater than 1 bar (ga). “Pot“ mounted is the installation of a complete pump assembly, process auxiliaries and power connections in a pressure vessel. Pressurised storage service is the handling of liquefied butane or lighter hydrocarbons stored in pressurised vessels at specified temperature. -Rated discharge pressure is the discharge pressure developed by the pump at the guarantee point with the furnished impeller size and at rated flow, speed, suction pressure and density. -Rated flow is the flow at the guarantee point. -Rated power is the power required by the pump at the guarantee point. -Refrigerated product service is the handling of butane or lighter hydrocarbons which are in the liquid phase under atmospheric pressure. -Rated suction pressure is the specified suction pressure of the pump at the guarantee point. 1.4CROSS-REFERENCES Where cross-references to other parts of this DEP are made, the referenced section number is shown in brackets. Other documents referenced by this DEP are listed in (5.). DEP 31.29.06.30-Gen. December 1996 Page 6 2.DESIGN 2.1GENERAL (a)Pump ratings shall not exceed the limits of the Manufacturer's design and shall be within the Manufacturer's actual experience, i.e. there shall be no extrapolation from existing models/ types. Equipment shall have been proven in similar service. At least 3 units of the similar type and size shall have had at least 8000 hours of continuous operation each. (b)Pumps with constant-speed drivers shall be capable of at least a 5% head increase at rated conditions with the impeller(s) replaced by impeller(s) of larger diameter or different prove